Typewriting machine



Sept. 18, 1934. w. A. DOBSON TIIREWRITING MACHINE Fii d "se t. 9, 1929 WWW/72W by 6%" mvenfor:

A770 my Patented Sept. 18, 1934 'I "WW /ix f-TYPEWRITINGfMAoni'NE' Willia A. DobsonjBi-idgeport, com, as'signor to UnderwoodElliott Fisher Company, New York; N. Y., a corporation'of Delaware I Application Sept mb r 9, 1929, Serial No. 391,133

{:2 Claims (01. 197 -18 3) This invention relates to improvements in stops or anvilsfor thetype-bars of typewriting machines. The typewriter-segment which is best suited to general use is cast in one piece, and the metal best suited for all of the requirements of a portable typewriter-segment is an aluminum alloy. All of the exposed metal parts of the portable typewriter, of which the segment is one, are of polished non-corrosive metals, and anything that 10 tends to destroy this polish detracts from the appearance and desirability of the machine. Constant hammering of the type-bars on the anvil not only destroys the polish and covers the face of the anvil with black marks, but, on account of the -metal being comparatively soft, it pits the surface of the anvil, producing shallow depressions or notches.

These depressions cause imperfect type-impressions on the platen, and eventually make it necessary to replace the expensive segment.

One object of this invention is to overcome these objections.

Another object of this invention is to keep the expense of replacements at a minimum, and to produce a device in simple form, which is light, durable and attractive.

Another object of this invention is to reduce the noise now resulting when the type-bars strike the common one-piece segment. This reduction of noise is partly due to the fact that two parts having different rates of vibration when struck are securely fastened together to form the stop or anvil.

With these and other objects in view, this invention includes an arcuate facing in the form of a punching of thin hard-drawn sheet-metal removably packed against the segment by screws, the segment having a machined-raised seat to constantly contact with and support the punching, which therefore as an integument to said seat presents a hard anvil-face for the type-bars to strike against before typing upon the platen. This anvil-face may be renewed at any time at little expense, and because of the accurate mill-gaging of the sheet-metal thereof, it becomes an interchangeable product that can be substituted in any machine without disturbing the alignment of the type-bars.

j Other features and advantages will hereinafter appear.

In the accompanying drawing, Figure 1 shows a front view of the invention attached to the usual segment of an Underwood iiportable typewriter.

Figure 2 shows a partial side view with thesegmerit and stop'plate in section.

'Figure 3' is afragmentary perspective view partly in section of a segment, showing the construction and attachment of the working surface in detail.

Referring to the drawing, in Figure 1 is shown a platen 10 and a type-bar 11 in position for making a forced impression on the platen. A guide-plate 12 for guiding the type 13 to exact position for printing is secured to a segment 14 in the ordinary way. The type-bars 11 are housed in slots 15 and pivoted on a fulcrum-rod 19 of the segment 14 which is made in one piece and cast of aluminum. Part of this casting is in the form of an annular ridge, anvil or base-support 16 which has heretofore been used as a stop for a lug 1'7 on the type-bars 11.

In order to apply this invention, the regular annular segmental ridge 16 is machined to support a thin metal plate, facing or anvil 20 which is made of hard-drawn metal such as steel, Monelmetal, or the like, and shaped in the form of an arc of the same radius as the annular ridge 16 to combine with it and act as a stop or anvil for the type-bars, the hard facing preventing indentation by the latter, and having wear-resisting characteristics. The outer edge 21 of the arcshaped plate or anvil is bent downwardly at right angles, and may be adapted to the depth of the annular ridge 16.

At the center of the arc-shaped plate 20, and

in the depression 23 between the ridge 16 and the slotted section 16*, is a lug or ear 22 attached to or integral with said arc-shaped plate 20, which helps to secure the plate 20 in place by means of a screw 24. The ends of the plate 20 are held or packed down upon the stop-ridge 16 by other screws 25 and 26. This plate 20 is shaped to fit the stop-ridge 16 neatly, and by reason of the difference in density of the metals for the plate 20 and the stop-ridge 16, they counteract one another and quiet impact of the typebars is the result.

When the arc-shaped plate 20 becomes marred or worn, all that is necessary is to remove the screws 24, 25 and 26 and substitute a new plate, and this part of the typewriting machine is renewed to look as good as new.

It will be noted that the anvil-facing 20 may be made at a single operation by a combination blanking, piercing and forming die; that the anvil-facing may be punched from a cold-rolled sheet-metal having a maximum hardness or density that will stand the bending of the ears 22 without fracture; that the thickness of such a metal can be held within close gage limits of half a thousandths; that any anvil-facing struck of the proper thickness from such a metal can be substituted in any machine having the annular ridge 16 of proper thickness, at any time, and in any place without disturbing the printing efiect of the prealigned type-bar system; that an anvil made as described, reduces the production costs to a minimum, and raises the efficiency to a maximum; that the substitution is so simple that a novice can replace a pitted anvil; that the anvil-face at all times is a rigid abutment for the type-bars to strike against before printing,

upon the platen; and that the relation of the anvil to the type-bars is such that the type-bars may strike the anvil lightly and not print, but the usual typing impact thereagainst willcause the type-end to whip over the anvil to print against the platen in a well-known Underwood manner.

The type-bars 11 areformed at their lower ends with hooks 18 fulcrumed" on the rod 19 in the usual manner.

Variations may be resorted to within the scope of the invention, and portions of the improvements may be used without others.

Having thus described my invention, I claim:

1. The combination of a platen, a segment having type bars, an anvil on the segment to be struck by the type bars in printing on the platen and .means to prevent pitting of the anvil from the impact of the type bars, said means comprising a hard sheet metal armouring plate secured to the impact face of the anvil in intimate surface contact therewith and forming a rigid impact face against' 'which the type bars strike.'

2. Asoft metal type bar segment having a ridge 'for arresting type bars and a detachable armour of thinsheet metal harder than said ridge secured to the segment to form the impact face of the ridge'and in intimate surface contact therewith constituting a rigid impact face against which the type bars strike.

WILLIAM A. DOBSON. 

